Revalidate cache, retrieve data once cache expires
Revalidate cache, retrieve data once cache expires

"proxy-revalidate" recommended by Cloudflare, where "must-revalidate" is
the same.

Resources
https://blog.cloudflare.com/theres-always-cache-in-the-banana-stand/

https://stackoverflow.com/questions/18148884/difference-between-no-cache-and-must-revalidate

laukstein/ajax-seo,laukstein/ajax-seo